Motek K-10

Additional Info

From Tape Recording & Hi-Fi Magazine (fortnightly) 10th February 1960

THE Motek K.10 may well prove the answer to those home constructors whose problem is the choice of a low-priced and reasonably efficient three-speed deck. It is simple; simplicity is often said to be the keynote of efficiency, and most of the facilities required for a good general purpose tape recorder are here included.
It is fitted with a large and well-turned flywheel/capstan and three motors take care of the drive system. Controls are push-button type, which operate a series of switches with plenty of spare contacts for HT, erase head, and changeover from recording to playback amplifiers. A pause button is provided, as well as an interlocking safety switch for recording, which also serves as a useful reminder that there may already be something on the tape that shouldn’t be erased.
A drum-type tape position indicator is fitted and the tape hubs have screw-on spool locks. These prevent the spools coming adrift if the deck is used in a portable recorder and reduce spool vibration on the very fast re-wind that is available by the use of separate motors for each spool.
Rewind time for a seven-inch spool of tape (1,200 ft.) is approximately one minute.
The deck is nicely finished, in two shades of grey with white controls and tape head cover, and actually comprises two plates, the lower one being of pressed steel, which overcomes warping and consequent misalignment of bearings and mechanism.
Mechanical band brakes operate from the push-button controls and have a very definite and fast action on both normal running and re-wind. The deck reviewed was for 220/250 volts 50 cps mains operation, with three operating speeds: 7½ ips, 3¾ ips and 1 ips.
The record and playback consumption is 70 watts, and during fast wind, 120 watts.
A half-track record/playback head and an erase head are fitted with a tape pressure pad system mechanically operated from the push-button controls.
The five push-buttons provide the following functions: playback, record, fast forward and reverse re-wind and stop, with the pause button and speed switch as separate controls.
I can quote no maker’s figure for wow and flutter percentage as none were given.
All controls were checked for correct operation and all performed properly. The tape position indicator was accurate enough, as most of this type are, to find a given place on the tape. The three speeds were correctly related to each other, complying favourably with normal performance specifications.
With a frequency test tape one can easily check the relationship of speeds that are each a half of the other. For example, a tone of say 1,000 cps recorded at 7½ ips will, or should, drop exactly one octave when played at 3¾ ips and should be two octaves lower at 1 ips. It should be an octave higher at 15ips.
To return to the Motek deck, I did detect very slight wow at the lower speeds and occasional vibration from the pressure pads. Braking is almost instantaneous and the tape rides smoothly in the guides and winds evenly on to the take-up spool on normal playing or fast wind. The tape head cover is removable to permit azimuth alignment of the tape head, for which two adjusting screws are provided at the base.
I would suggest that the tape head be provided with some mu-metal screening or a hum bucking coil; this may be necessary when the deck is fitted near a mains transformer, as there is already some hum pick-up from the motors when they are running.
FREQUENCY RESPONSE TESTS
The deck was tested in conjunction with a Mullard Type C recording amplifier and a Mullard 510 amplifier with a C.C.I.R. corrected tape pre-amplifier in front. Pre-recorded music was well reproduced, but required some treble boosting for a more brilliant response at the high frequencies. The head is capable of good recording and erase is clean, providing a suitable oscillator is used.
The newly-designed Motek head is a high impedance device (no transformer required). The makers claim that with a suitable amplifier the response is better than 40-12,000 cps at the higher speed using medium grade tape.
Previous designs of the Motek decks have included a high impedance erase head, this new model is fitted with a low impedance head of radiometal lamination construction to secure maximum performance.
The tape deck was tested for frequency response with the aid of an E.M.I. TBTl test tape for 7½ ips and a specially recorded test tape for the other two speeds. The response curves for 7½ ips and 3¾ ips are shown in Fig. 1, but these may vary very considerably with the type of amplifiers used. They do, however, indicate the capabilities of the tape head fitted to the Motek K.10 deck and could no doubt be improved upon by careful design of the amplifiers to be used with it.
The record head is mounted on a precision bearing located under the head-seating plate below the head. By suitable adjustment of the two screws on the left and right of the head, the gap line can be set to a very fine degree of accuracy and for the best possible results from pre-recorded tapes. Alternatively, the gap line can be deliberately off set to obtain good play back reproduction from a tape recorded on another machine with a misaligned head.
Because of its low price the K.10 should certainly appeal to the home constructor with a not too deep pocket who wants a serviceable and adaptable deck for building an inexpensive recorder. It is recommended for this purpose, and I may add that many manufacturers already incorporate this deck in their recorders-a good indication of a deck with a satisfactory performance.
All metal parts are tropicalised Cadmium plated. The dimensions of the deck are 15¼ x 10¾ x 4 inches, weight, 13¾ lb. The list price is 21 guineas.